(+)-Epiexcelsin 51020-09-8 6-[(2S,6R)-6-(7-Methoxy(2H-benzo[3,4-d]1,3-dioxolen-5-yl))-3,7-dioxabicyclo[3.3.0]oct-2-yl]-4-methoxy-2H-benzo[d]1,3-dioxolene AIDS-113498 AIDS113498